[people/ms/linux.git] / fs / readdir.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/readdir.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/dirent.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/compat.h>
#include <linux/uaccess.h>

#include <asm/unaligned.h>

/*
 * Note the "unsafe_put_user() semantics: we goto a
 * label for errors.
 *
 * Also note how we use a "while()" loop here, even though
 * only the biggest size needs to loop. The compiler (well,
 * at least gcc) is smart enough to turn the smaller sizes
 * into just if-statements, and this way we don't need to
 * care whether 'u64' or 'u32' is the biggest size.
 */
#define unsafe_copy_loop(dst, src, len, type, label) 		\
	while (len >= sizeof(type)) {				\
		unsafe_put_user(get_unaligned((type *)src),	\
			(type __user *)dst, label);		\
		dst += sizeof(type);				\
		src += sizeof(type);				\
		len -= sizeof(type);				\
	}

/*
 * We avoid doing 64-bit copies on 32-bit architectures. They
 * might be better, but the component names are mostly small,
 * and the 64-bit cases can end up being much more complex and
 * put much more register pressure on the code, so it's likely
 * not worth the pain of unaligned accesses etc.
 *
 * So limit the copies to "unsigned long" size. I did verify
 * that at least the x86-32 case is ok without this limiting,
 * but I worry about random other legacy 32-bit cases that
 * might not do as well.
 */
#define unsafe_copy_type(dst, src, len, type, label) do {	\
	if (sizeof(type) <= sizeof(unsigned long))		\
		unsafe_copy_loop(dst, src, len, type, label);	\
} while (0)

/*
 * Copy the dirent name to user space, and NUL-terminate
 * it. This should not be a function call, since we're doing
 * the copy inside a "user_access_begin/end()" section.
 */
#define unsafe_copy_dirent_name(_dst, _src, _len, label) do {	\
	char __user *dst = (_dst);				\
	const char *src = (_src);				\
	size_t len = (_len);					\
	unsafe_copy_type(dst, src, len, u64, label);	 	\
	unsafe_copy_type(dst, src, len, u32, label);		\
	unsafe_copy_type(dst, src, len, u16, label);		\
	unsafe_copy_type(dst, src, len, u8,  label);		\
	unsafe_put_user(0, dst, label);				\
} while (0)


int iterate_dir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	bool shared = false;
	int res = -ENOTDIR;
	if (file->f_op->iterate_shared)
		shared = true;
	else if (!file->f_op->iterate)
		goto out;

	res = security_file_permission(file, MAY_READ);
	if (res)
		goto out;

	if (shared)
		res = down_read_killable(&inode->i_rwsem);
	else
		res = down_write_killable(&inode->i_rwsem);
	if (res)
		goto out;

	res = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		ctx->pos = file->f_pos;
		if (shared)
			res = file->f_op->iterate_shared(file, ctx);
		else
			res = file->f_op->iterate(file, ctx);
		file->f_pos = ctx->pos;
		fsnotify_access(file);
		file_accessed(file);
	}
	if (shared)
		inode_unlock_shared(inode);
	else
		inode_unlock(inode);
out:
	return res;
}
EXPORT_SYMBOL(iterate_dir);

/*
 * Traditional linux readdir() handling..
 *
 * "count=1" is a special case, meaning that the buffer is one
 * dirent-structure in size and that the code can't handle more
 * anyway. Thus the special "fillonedir()" function for that
 * case (the low-level handlers don't need to care about this).
 */

#ifdef __ARCH_WANT_OLD_READDIR

struct old_linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct readdir_callback {
	struct dir_context ctx;
	struct old_linux_dirent __user * dirent;
	int result;
};

static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
		      loff_t offset, u64 ino, unsigned int d_type)
{
	struct readdir_callback *buf =
		container_of(ctx, struct readdir_callback, ctx);
	struct old_linux_dirent __user * dirent;
	unsigned long d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
		struct old_linux_dirent __user *, dirent, unsigned int, count)
{
	int error;
	struct fd f = fdget_pos(fd);
	struct readdir_callback buf = {
		.ctx.actor = fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (buf.result)
		error = buf.result;

	fdput_pos(f);
	return error;
}

#endif /* __ARCH_WANT_OLD_READDIR */

/*
 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
 * interface. 
 */
struct linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct getdents_callback {
	struct dir_context ctx;
	struct linux_dirent __user * current_dir;
	struct linux_dirent __user * previous;
	int count;
	int error;
};

static int filldir(struct dir_context *ctx, const char *name, int namlen,
		   loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent __user * dirent;
	struct getdents_callback *buf =
		container_of(ctx, struct getdents_callback, ctx);
	unsigned long d_ino;
	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
		sizeof(long));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent && signal_pending(current))
		return -EINTR;

	/*
	 * Note! This range-checks 'previous' (which may be NULL).
	 * The real range was checked in getdents
	 */
	if (!user_access_begin(dirent, sizeof(*dirent)))
		goto efault;
	if (dirent)
		unsafe_put_user(offset, &dirent->d_off, efault_end);
	dirent = buf->current_dir;
	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_access_end();

	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault_end:
	user_access_end();
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(getdents, unsigned int, fd,
		struct linux_dirent __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct linux_dirent __user * lastdirent;
	struct getdents_callback buf = {
		.ctx.actor = filldir,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(buf.ctx.pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}

struct getdents_callback64 {
	struct dir_context ctx;
	struct linux_dirent64 __user * current_dir;
	struct linux_dirent64 __user * previous;
	int count;
	int error;
};

static int filldir64(struct dir_context *ctx, const char *name, int namlen,
		     loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct getdents_callback64 *buf =
		container_of(ctx, struct getdents_callback64, ctx);
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
		sizeof(u64));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	dirent = buf->previous;
	if (dirent && signal_pending(current))
		return -EINTR;

	/*
	 * Note! This range-checks 'previous' (which may be NULL).
	 * The real range was checked in getdents
	 */
	if (!user_access_begin(dirent, sizeof(*dirent)))
		goto efault;
	if (dirent)
		unsafe_put_user(offset, &dirent->d_off, efault_end);
	dirent = buf->current_dir;
	unsafe_put_user(ino, &dirent->d_ino, efault_end);
	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	unsafe_put_user(d_type, &dirent->d_type, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_access_end();

	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault_end:
	user_access_end();
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
		    unsigned int count)
{
	struct fd f;
	struct linux_dirent64 __user * lastdirent;
	struct getdents_callback64 buf = {
		.ctx.actor = filldir64,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		typeof(lastdirent->d_off) d_off = buf.ctx.pos;
		if (__put_user(d_off, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}


SYSCALL_DEFINE3(getdents64, unsigned int, fd,
		struct linux_dirent64 __user *, dirent, unsigned int, count)
{
	return ksys_getdents64(fd, dirent, count);
}

#ifdef CONFIG_COMPAT
struct compat_old_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct compat_readdir_callback {
	struct dir_context ctx;
	struct compat_old_linux_dirent __user *dirent;
	int result;
};

static int compat_fillonedir(struct dir_context *ctx, const char *name,
			     int namlen, loff_t offset, u64 ino,
			     unsigned int d_type)
{
	struct compat_readdir_callback *buf =
		container_of(ctx, struct compat_readdir_callback, ctx);
	struct compat_old_linux_dirent __user *dirent;
	compat_ulong_t d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
		struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
{
	int error;
	struct fd f = fdget_pos(fd);
	struct compat_readdir_callback buf = {
		.ctx.actor = compat_fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (buf.result)
		error = buf.result;

	fdput_pos(f);
	return error;
}

struct compat_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct compat_getdents_callback {
	struct dir_context ctx;
	struct compat_linux_dirent __user *current_dir;
	struct compat_linux_dirent __user *previous;
	int count;
	int error;
};

static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
		loff_t offset, u64 ino, unsigned int d_type)
{
	struct compat_linux_dirent __user * dirent;
	struct compat_getdents_callback *buf =
		container_of(ctx, struct compat_getdents_callback, ctx);
	compat_ulong_t d_ino;
	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
		namlen + 2, sizeof(compat_long_t));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent) {
		if (signal_pending(current))
			return -EINTR;
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(d_ino, &dirent->d_ino))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	if (__put_user(d_type, (char  __user *) dirent + reclen - 1))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
		struct compat_linux_dirent __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct compat_linux_dirent __user * lastdirent;
	struct compat_getdents_callback buf = {
		.ctx.actor = compat_filldir,
		.current_dir = dirent,
		.count = count
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(buf.ctx.pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/readdir.c
	4	*
	5	* Copyright (C) 1995 Linus Torvalds
	6	*/
	7
85c9fe8f	8	#include <linux/stddef.h>
022a1692	9	#include <linux/kernel.h>
630d9c47	10	#include <linux/export.h>
1da177e4 LT	11	#include <linux/time.h>
	12	#include <linux/mm.h>
	13	#include <linux/errno.h>
	14	#include <linux/stat.h>
	15	#include <linux/file.h>
1da177e4	16	#include <linux/fs.h>
d4c7cf6c	17	#include <linux/fsnotify.h>
1da177e4 LT	18	#include <linux/dirent.h>
	19	#include <linux/security.h>
	20	#include <linux/syscalls.h>
	21	#include <linux/unistd.h>
0460b2a2	22	#include <linux/compat.h>
7c0f6ba6	23	#include <linux/uaccess.h>
1da177e4	24
9f79b78e LT	25	#include <asm/unaligned.h>
	26
	27	/*
	28	* Note the "unsafe_put_user() semantics: we goto a
	29	* label for errors.
	30	*
	31	* Also note how we use a "while()" loop here, even though
	32	* only the biggest size needs to loop. The compiler (well,
	33	* at least gcc) is smart enough to turn the smaller sizes
	34	* into just if-statements, and this way we don't need to
	35	* care whether 'u64' or 'u32' is the biggest size.
	36	*/
	37	#define unsafe_copy_loop(dst, src, len, type, label) \
	38	while (len >= sizeof(type)) { \
	39	unsafe_put_user(get_unaligned((type *)src), \
	40	(type __user *)dst, label); \
	41	dst += sizeof(type); \
	42	src += sizeof(type); \
	43	len -= sizeof(type); \
	44	}
	45
	46	/*
	47	* We avoid doing 64-bit copies on 32-bit architectures. They
	48	* might be better, but the component names are mostly small,
	49	* and the 64-bit cases can end up being much more complex and
	50	* put much more register pressure on the code, so it's likely
	51	* not worth the pain of unaligned accesses etc.
	52	*
	53	* So limit the copies to "unsigned long" size. I did verify
	54	* that at least the x86-32 case is ok without this limiting,
	55	* but I worry about random other legacy 32-bit cases that
	56	* might not do as well.
	57	*/
	58	#define unsafe_copy_type(dst, src, len, type, label) do { \
	59	if (sizeof(type) <= sizeof(unsigned long)) \
	60	unsafe_copy_loop(dst, src, len, type, label); \
	61	} while (0)
	62
	63	/*
	64	* Copy the dirent name to user space, and NUL-terminate
	65	* it. This should not be a function call, since we're doing
	66	* the copy inside a "user_access_begin/end()" section.
	67	*/
	68	#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
	69	char __user *dst = (_dst); \
	70	const char *src = (_src); \
	71	size_t len = (_len); \
	72	unsafe_copy_type(dst, src, len, u64, label); \
	73	unsafe_copy_type(dst, src, len, u32, label); \
	74	unsafe_copy_type(dst, src, len, u16, label); \
	75	unsafe_copy_type(dst, src, len, u8, label); \
	76	unsafe_put_user(0, dst, label); \
	77	} while (0)
	78
	79
5c0ba4e0	80	int iterate_dir(struct file file, struct dir_context ctx)
1da177e4	81	{
496ad9aa	82	struct inode *inode = file_inode(file);
61922694	83	bool shared = false;
1da177e4	84	int res = -ENOTDIR;
61922694 AV	85	if (file->f_op->iterate_shared)
	86	shared = true;
	87	else if (!file->f_op->iterate)
1da177e4 LT	88	goto out;
	89
	90	res = security_file_permission(file, MAY_READ);
	91	if (res)
	92	goto out;
	93
0dc208b5 KT	94	if (shared)
	95	res = down_read_killable(&inode->i_rwsem);
	96	else
00235411	97	res = down_write_killable(&inode->i_rwsem);
0dc208b5 KT	98	if (res)
0dc208b5 KT	99	goto out;
da784511	100
1da177e4 LT	101	res = -ENOENT;
1da177e4 LT	102	if (!IS_DEADDIR(inode)) {
2233f31a	103	ctx->pos = file->f_pos;
61922694 AV	104	if (shared)
	105	res = file->f_op->iterate_shared(file, ctx);
	106	else
	107	res = file->f_op->iterate(file, ctx);
2233f31a	108	file->f_pos = ctx->pos;
d4c7cf6c	109	fsnotify_access(file);
1da177e4 LT	110	file_accessed(file);
1da177e4 LT	111	}
61922694 AV	112	if (shared)
	113	inode_unlock_shared(inode);
	114	else
	115	inode_unlock(inode);
1da177e4 LT	116	out:
	117	return res;
	118	}
5c0ba4e0	119	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	120
	121	/*
	122	* Traditional linux readdir() handling..
	123	*
	124	* "count=1" is a special case, meaning that the buffer is one
	125	* dirent-structure in size and that the code can't handle more
	126	* anyway. Thus the special "fillonedir()" function for that
	127	* case (the low-level handlers don't need to care about this).
	128	*/
1da177e4 LT	129
	130	#ifdef __ARCH_WANT_OLD_READDIR
	131
	132	struct old_linux_dirent {
	133	unsigned long d_ino;
	134	unsigned long d_offset;
	135	unsigned short d_namlen;
	136	char d_name[1];
	137	};
	138
	139	struct readdir_callback {
5c0ba4e0	140	struct dir_context ctx;
1da177e4 LT	141	struct old_linux_dirent __user * dirent;
	142	int result;
	143	};
	144
ac7576f4 MS	145	static int fillonedir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	146	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	147	{
ac7576f4 MS	148	struct readdir_callback *buf =
ac7576f4 MS	149	container_of(ctx, struct readdir_callback, ctx);
1da177e4	150	struct old_linux_dirent __user * dirent;
afefdbb2	151	unsigned long d_ino;
1da177e4 LT	152
	153	if (buf->result)
	154	return -EINVAL;
afefdbb2	155	d_ino = ino;
8f3f655d AV	156	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	157	buf->result = -EOVERFLOW;
afefdbb2	158	return -EOVERFLOW;
8f3f655d	159	}
1da177e4 LT	160	buf->result++;
1da177e4 LT	161	dirent = buf->dirent;
96d4f267	162	if (!access_ok(dirent,
1da177e4 LT	163	(unsigned long)(dirent->d_name + namlen + 1) -
	164	(unsigned long)dirent))
	165	goto efault;
afefdbb2	166	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	167	__put_user(offset, &dirent->d_offset) \|\|
	168	__put_user(namlen, &dirent->d_namlen) \|\|
	169	__copy_to_user(dirent->d_name, name, namlen) \|\|
	170	__put_user(0, dirent->d_name + namlen))
	171	goto efault;
	172	return 0;
	173	efault:
	174	buf->result = -EFAULT;
	175	return -EFAULT;
	176	}
	177
d4e82042 HC	178	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	179	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	180	{
1da177e4 LT	181	int error;
63b6df14	182	struct fd f = fdget_pos(fd);
ac6614b7 AV	183	struct readdir_callback buf = {
	184	.ctx.actor = fillonedir,
	185	.dirent = dirent
	186	};
1da177e4	187
2903ff01	188	if (!f.file)
863ced7f	189	return -EBADF;
1da177e4	190
5c0ba4e0	191	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	192	if (buf.result)
1da177e4 LT	193	error = buf.result;
1da177e4 LT	194
63b6df14	195	fdput_pos(f);
1da177e4 LT	196	return error;
	197	}
	198
	199	#endif /* __ARCH_WANT_OLD_READDIR */
	200
	201	/*
	202	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	203	* interface.
	204	*/
	205	struct linux_dirent {
	206	unsigned long d_ino;
	207	unsigned long d_off;
	208	unsigned short d_reclen;
	209	char d_name[1];
	210	};
	211
	212	struct getdents_callback {
5c0ba4e0	213	struct dir_context ctx;
1da177e4 LT	214	struct linux_dirent __user * current_dir;
	215	struct linux_dirent __user * previous;
	216	int count;
	217	int error;
	218	};
	219
ac7576f4 MS	220	static int filldir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	221	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	222	{
1da177e4 LT	223	struct linux_dirent __user * dirent;
ac7576f4 MS	224	struct getdents_callback *buf =
ac7576f4 MS	225	container_of(ctx, struct getdents_callback, ctx);
afefdbb2	226	unsigned long d_ino;
85c9fe8f KW	227	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	228	sizeof(long));
1da177e4 LT	229
	230	buf->error = -EINVAL; /* only used if we fail.. */
	231	if (reclen > buf->count)
	232	return -EINVAL;
afefdbb2	233	d_ino = ino;
8f3f655d AV	234	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	235	buf->error = -EOVERFLOW;
afefdbb2	236	return -EOVERFLOW;
8f3f655d	237	}
1da177e4	238	dirent = buf->previous;
9f79b78e LT	239	if (dirent && signal_pending(current))
	240	return -EINTR;
	241
	242	/*
	243	* Note! This range-checks 'previous' (which may be NULL).
	244	* The real range was checked in getdents
	245	*/
	246	if (!user_access_begin(dirent, sizeof(*dirent)))
1da177e4	247	goto efault;
9f79b78e LT	248	if (dirent)
	249	unsafe_put_user(offset, &dirent->d_off, efault_end);
	250	dirent = buf->current_dir;
	251	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	252	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	253	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	254	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	255	user_access_end();
	256
1da177e4 LT	257	buf->previous = dirent;
	258	dirent = (void __user *)dirent + reclen;
	259	buf->current_dir = dirent;
	260	buf->count -= reclen;
	261	return 0;
9f79b78e LT	262	efault_end:
9f79b78e LT	263	user_access_end();
1da177e4 LT	264	efault:
	265	buf->error = -EFAULT;
	266	return -EFAULT;
	267	}
	268
20f37034 HC	269	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	270	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	271	{
2903ff01	272	struct fd f;
1da177e4	273	struct linux_dirent __user * lastdirent;
ac6614b7 AV	274	struct getdents_callback buf = {
	275	.ctx.actor = filldir,
	276	.count = count,
	277	.current_dir = dirent
	278	};
1da177e4 LT	279	int error;
1da177e4 LT	280
96d4f267	281	if (!access_ok(dirent, count))
863ced7f	282	return -EFAULT;
1da177e4	283
63b6df14	284	f = fdget_pos(fd);
2903ff01	285	if (!f.file)
863ced7f	286	return -EBADF;
1da177e4	287
5c0ba4e0	288	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	289	if (error >= 0)
53c9c5c0 AV	290	error = buf.error;
1da177e4 LT	291	lastdirent = buf.previous;
1da177e4 LT	292	if (lastdirent) {
bb6f619b	293	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	294	error = -EFAULT;
	295	else
	296	error = count - buf.count;
	297	}
63b6df14	298	fdput_pos(f);
1da177e4 LT	299	return error;
	300	}
	301
1da177e4	302	struct getdents_callback64 {
5c0ba4e0	303	struct dir_context ctx;
1da177e4 LT	304	struct linux_dirent64 __user * current_dir;
	305	struct linux_dirent64 __user * previous;
	306	int count;
	307	int error;
	308	};
	309
ac7576f4 MS	310	static int filldir64(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	311	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	312	{
1da177e4 LT	313	struct linux_dirent64 __user *dirent;
ac7576f4 MS	314	struct getdents_callback64 *buf =
ac7576f4 MS	315	container_of(ctx, struct getdents_callback64, ctx);
85c9fe8f KW	316	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	317	sizeof(u64));
1da177e4 LT	318
	319	buf->error = -EINVAL; /* only used if we fail.. */
	320	if (reclen > buf->count)
	321	return -EINVAL;
	322	dirent = buf->previous;
9f79b78e LT	323	if (dirent && signal_pending(current))
	324	return -EINTR;
	325
	326	/*
	327	* Note! This range-checks 'previous' (which may be NULL).
	328	* The real range was checked in getdents
	329	*/
	330	if (!user_access_begin(dirent, sizeof(*dirent)))
1da177e4	331	goto efault;
9f79b78e LT	332	if (dirent)
	333	unsafe_put_user(offset, &dirent->d_off, efault_end);
	334	dirent = buf->current_dir;
	335	unsafe_put_user(ino, &dirent->d_ino, efault_end);
	336	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	337	unsafe_put_user(d_type, &dirent->d_type, efault_end);
	338	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	339	user_access_end();
	340
1da177e4 LT	341	buf->previous = dirent;
	342	dirent = (void __user *)dirent + reclen;
	343	buf->current_dir = dirent;
	344	buf->count -= reclen;
	345	return 0;
9f79b78e LT	346	efault_end:
9f79b78e LT	347	user_access_end();
1da177e4 LT	348	efault:
	349	buf->error = -EFAULT;
	350	return -EFAULT;
	351	}
	352
454dab3f DB	353	int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
454dab3f DB	354	unsigned int count)
1da177e4	355	{
2903ff01	356	struct fd f;
1da177e4	357	struct linux_dirent64 __user * lastdirent;
ac6614b7 AV	358	struct getdents_callback64 buf = {
	359	.ctx.actor = filldir64,
	360	.count = count,
	361	.current_dir = dirent
	362	};
1da177e4 LT	363	int error;
1da177e4 LT	364
96d4f267	365	if (!access_ok(dirent, count))
863ced7f	366	return -EFAULT;
1da177e4	367
63b6df14	368	f = fdget_pos(fd);
2903ff01	369	if (!f.file)
863ced7f	370	return -EBADF;
1da177e4	371
5c0ba4e0	372	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	373	if (error >= 0)
53c9c5c0 AV	374	error = buf.error;
1da177e4 LT	375	lastdirent = buf.previous;
1da177e4 LT	376	if (lastdirent) {
bb6f619b	377	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	378	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	379	error = -EFAULT;
	380	else
	381	error = count - buf.count;
1da177e4	382	}
63b6df14	383	fdput_pos(f);
1da177e4 LT	384	return error;
1da177e4 LT	385	}
0460b2a2	386
454dab3f DB	387
	388	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
	389	struct linux_dirent64 __user *, dirent, unsigned int, count)
	390	{
	391	return ksys_getdents64(fd, dirent, count);
	392	}
	393
0460b2a2 AV	394	#ifdef CONFIG_COMPAT
	395	struct compat_old_linux_dirent {
	396	compat_ulong_t d_ino;
	397	compat_ulong_t d_offset;
	398	unsigned short d_namlen;
	399	char d_name[1];
	400	};
	401
	402	struct compat_readdir_callback {
	403	struct dir_context ctx;
	404	struct compat_old_linux_dirent __user *dirent;
	405	int result;
	406	};
	407
	408	static int compat_fillonedir(struct dir_context ctx, const char name,
	409	int namlen, loff_t offset, u64 ino,
	410	unsigned int d_type)
	411	{
	412	struct compat_readdir_callback *buf =
	413	container_of(ctx, struct compat_readdir_callback, ctx);
	414	struct compat_old_linux_dirent __user *dirent;
	415	compat_ulong_t d_ino;
	416
	417	if (buf->result)
	418	return -EINVAL;
	419	d_ino = ino;
	420	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
	421	buf->result = -EOVERFLOW;
	422	return -EOVERFLOW;
	423	}
	424	buf->result++;
	425	dirent = buf->dirent;
96d4f267	426	if (!access_ok(dirent,
0460b2a2 AV	427	(unsigned long)(dirent->d_name + namlen + 1) -
	428	(unsigned long)dirent))
	429	goto efault;
	430	if ( __put_user(d_ino, &dirent->d_ino) \|\|
	431	__put_user(offset, &dirent->d_offset) \|\|
	432	__put_user(namlen, &dirent->d_namlen) \|\|
	433	__copy_to_user(dirent->d_name, name, namlen) \|\|
	434	__put_user(0, dirent->d_name + namlen))
	435	goto efault;
	436	return 0;
	437	efault:
	438	buf->result = -EFAULT;
	439	return -EFAULT;
	440	}
	441
	442	COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
	443	struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
	444	{
	445	int error;
	446	struct fd f = fdget_pos(fd);
	447	struct compat_readdir_callback buf = {
	448	.ctx.actor = compat_fillonedir,
	449	.dirent = dirent
	450	};
	451
	452	if (!f.file)
	453	return -EBADF;
	454
	455	error = iterate_dir(f.file, &buf.ctx);
	456	if (buf.result)
	457	error = buf.result;
	458
	459	fdput_pos(f);
	460	return error;
	461	}
	462
	463	struct compat_linux_dirent {
	464	compat_ulong_t d_ino;
	465	compat_ulong_t d_off;
	466	unsigned short d_reclen;
	467	char d_name[1];
	468	};
	469
	470	struct compat_getdents_callback {
	471	struct dir_context ctx;
	472	struct compat_linux_dirent __user *current_dir;
	473	struct compat_linux_dirent __user *previous;
	474	int count;
	475	int error;
	476	};
	477
	478	static int compat_filldir(struct dir_context ctx, const char name, int namlen,
	479	loff_t offset, u64 ino, unsigned int d_type)
	480	{
	481	struct compat_linux_dirent __user * dirent;
	482	struct compat_getdents_callback *buf =
	483	container_of(ctx, struct compat_getdents_callback, ctx);
	484	compat_ulong_t d_ino;
	485	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
	486	namlen + 2, sizeof(compat_long_t));
	487
	488	buf->error = -EINVAL; /* only used if we fail.. */
	489	if (reclen > buf->count)
	490	return -EINVAL;
491	d_ino = ino;
492	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
493	buf->error = -EOVERFLOW;
494	return -EOVERFLOW;
495	}
496	dirent = buf->previous;
497	if (dirent) {
498	if (signal_pending(current))
499	return -EINTR;
500	if (__put_user(offset, &dirent->d_off))
501	goto efault;
502	}
503	dirent = buf->current_dir;
504	if (__put_user(d_ino, &dirent->d_ino))
505	goto efault;
506	if (__put_user(reclen, &dirent->d_reclen))
507	goto efault;
508	if (copy_to_user(dirent->d_name, name, namlen))
509	goto efault;
510	if (__put_user(0, dirent->d_name + namlen))
511	goto efault;
512	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
513	goto efault;
514	buf->previous = dirent;
515	dirent = (void __user *)dirent + reclen;
516	buf->current_dir = dirent;
517	buf->count -= reclen;
518	return 0;
519	efault:
520	buf->error = -EFAULT;
521	return -EFAULT;
522	}
523
524	COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
525	struct compat_linux_dirent __user *, dirent, unsigned int, count)
526	{
527	struct fd f;
528	struct compat_linux_dirent __user * lastdirent;
529	struct compat_getdents_callback buf = {
530	.ctx.actor = compat_filldir,
531	.current_dir = dirent,
532	.count = count
533	};
534	int error;
535
96d4f267	536	if (!access_ok(dirent, count))
0460b2a2 AV	537	return -EFAULT;
	538
	539	f = fdget_pos(fd);
	540	if (!f.file)
	541	return -EBADF;
	542
	543	error = iterate_dir(f.file, &buf.ctx);
	544	if (error >= 0)
	545	error = buf.error;
	546	lastdirent = buf.previous;
	547	if (lastdirent) {
	548	if (put_user(buf.ctx.pos, &lastdirent->d_off))
	549	error = -EFAULT;
	550	else
	551	error = count - buf.count;
	552	}
	553	fdput_pos(f);
	554	return error;
	555	}
	556	#endif